Experimental study on biopsy sampling using new flexible cryoprobes: influence of activation time, probe size, tissue consistency, and contact pressure of the probe on the size of the biopsy specimen

Defining Optimal Settings for Lung Cryobiopsy in End-Stage Pulmonary Disease. A Human, Ex Vivo, Diseased Lung Clinical Trial

BACKGROUND

To evaluate optimal settings of probe size, freezing time, and distance to the pleura that influence the size and quality of biopsy specimens during transbronchial lung cryobiopsies in ESPD.

METHODS

We prospectively recruited 17 patients undergoing lung transplantation. We created a nonperfused ex vivo bronchoscopy setting to perform multiple cryobiopsies with different probe sizes (1.7, 1.9, and 2.4 mm), freezing times (3, 5, 7, 10, 20, 30 seconds), and probe distance from pleura (5, 10, and 20 mm). Alveolated pulmonary parenchyma area≥50% in histology was considered a good quality biopsy, with a minimum procedural artifact. We used logistic regression to identify independent parameters as risk factors for histologic adequacy.

RESULTS

A total of 545 cryobiopsies were obtained from 34 explanted lungs after pneumonectomy for lung transplantation. The mean maximum diameter of the specimen achieved with the 1.7 probe was larger (13.5 mm) than those obtained with 1.9 and 2.4 mm probes (11.3 and 10.7 mm, P= 0.07). More pleural macroscopic damage and pleural tissue in histology occurred with the 2.4 mm probe ( P <0.001). There was no difference in the quality of specimens between the different freezing times and the distance from the pleura.

CONCLUSIONS

Freezing time and distance from the pleura did not affect the histologic quality for diagnosing ESPD in severely damaged lungs. Smaller cryoprobe size did not negatively affect sample adequacy.

Transbronchial Cryobiopsy Using the Ultrathin 1.1-mm Cryoprobe with Ultrathin Bronchoscopy under Radial Endobronchial Ultrasound Guidance for Diagnosis of Peripheral Pulmonary Lesions

INTRODUCTION

Today, the increasing number of incidentally detected peripheral pulmonary lesions (PPLs) within and outside lung cancer screening trials is a diagnostic challenge. This fact encourages further improvement of diagnostic procedures to increase the diagnostic yield of transbronchial biopsy, which has been shown to have a low complication rate. The purpose of this study was to evaluate the safety and feasibility of a new ultrathin 1.1 cryoprobe that can be placed through an ultrathin bronchoscope (UTB) using fluoroscopy and radial endobronchial ultrasonography (rEBUS) navigation for assessing PPLs.

METHODS

Thirty-five patients with PPL less than 4 cm in diameter were prospectively enrolled to receive transbronchial cryobiopsies (TBCBs) using the ultrathin 1.1-mm cryoprobe. Navigation to the PPL was accomplished with the UTB. Under rEBUS and fluoroscopy guidance up to 4 cryobiopsies were obtained. The sample sizes of the biopsies were compared to a historic collective derived from a 1.9-mm cryoprobe and standard forceps. The feasibility and safety of the procedure, the cumulative and overall diagnostic yield, and the cryobiopsy sizes were evaluated.

RESULTS

After detection with the rEBUS, TBCB was collected from 35 PPLs, establishing a diagnosis in 25 cases, corresponding to an overall diagnostic yield of 71.4%. There was no difference in diagnostic yield for PPL <20 mm or ≥20 mm. All cryobiopsies were representative with a mean tissue area of 11.9 ± 4.3 mm2, which was significantly larger compared to the historic collective (p = 0.003). Six mild and four moderate bleeding events and 1 case of pneumothorax were observed.

CONCLUSIONS

Using the ultrathin 1.1-mm cryoprobe combined with an UTB for rEBUS-guided TBCB of PPL is feasible and safe. This diagnostic approach improves bronchoscopic techniques for diagnosing peripheral lung lesions and may contribute to improve diagnosis of lung cancer even in small PPL.

Applications of cryobiopsy in airway, pleural, and parenchymal disease

INTRODUCTION

:Cryobiopsy is a novel diagnostic technique for thoracic diseases which has been extensively investigated over the past 20 years. It was originally proposed for the diagnosis of endobronchial lesions and diffuse parenchymal lung disease due to limitations of conventional sampling techniques including small size and presence of artifacts.

AREAS COVERED

:We will review recent evidence related to the expanding use of cryobiopsy in thoracic diseases. To identify references, the MEDLINE database was searched from database inception until May 2022 for case series, cohort studies, randomized controlled trials, systematic reviews and meta-analyses related to cryobiopsy.

EXPERT OPINION

Cryobiopsy has expanding applications in the field of thoracic diseases. Evidence to support transbronchial cryobiopsy as an alternative to surgical lung biopsy is increasing and was recently endorsed as a conditional recommendation by the latest American Thoracic Society guideline update for Idiopathic Pulmonary Fibrosis. Developments in technology and technique, in particular the availability of a 1.1 mm flexible cryoprobe, have extended applications to pulmonary diseases, including diagnosis of interstitial lung diseases, peripheral pulmonary lesions, and lung transplant rejection.

Optimize Initial Freezing Time of Transbronchial Cryobiopsy for the Diagnosis of Interstitial Lung Disease: A Prospective Randomized Parallel Group Study

BACKGROUND

Transbronchial cryobiopsy (TBCB) is increasingly being identified as a potential alternative for the diagnosis of interstitial lung disease (ILD). The specimen size of TBCB is positively related to the freezing time. However, the proper initial freezing time for the clinical application of TBCB in ILD remains unknown.

METHODS

A prospective randomized parallel group study was employed to investigate ILD patients with unclear diagnosis, who were admitted to the First Affiliated Hospital of Guangzhou Medical University from May 2019 to October 2020 and required TBCB. All patients were randomly divided into 4 groups according to the different freezing times of TBCB: 3 s, 4 s, 5 s, and 6 s groups. All operations were performed under intravenous anesthesia with endotracheal intubation, 60-65 bar pressure of freezing gas source, and 1.9-mm cryoprobe. Compare differences among groups in specimen size, complications, pathological diagnosis efficiency, and multidisciplinary discussion (MDD) diagnostic efficiency.

RESULTS

A total of 100 patients were recruited and randomly assigned into 4 groups (n = 25 each group). The specimen sizes of TBCB in ILD were positively correlated with the freezing time (r = 0.639, p < 0.05). None of the patients experienced Grade 3 severe bleeding. Pneumothorax occurred in 1 patient in the 4 s, 5 s, and 6 s groups, respectively. The diagnostic yield of MDD in the 3 s, 4 s, 5 s, and 6 s groups were 64%, 88%, 88%, and 96%, respectively (p < 0.05), but showing no significant differences among 4 s, 5 s, and 6 s groups.

CONCLUSIONS

The specimen size and diagnostic efficiency of TBCB in ILD increased with a longer freezing time. When the freezing gas pressure is 60-65 bar, we recommended 4 s as the initial freezing time of TBCB, and this time is associated with high diagnostic efficiency and low incidence of complications.

Evaluation of Transbronchial Lung Cryobiopsy Freezing Time, Biopsy Size, Histological Quality, and Incidence of Complication: A Prospective Clinical Trial

BACKGROUND

Transbronchial cryobiopsy (TBCB), a novel way of obtaining a specimen of lung tissue using a flexible cryoprobe, can obtain large lung biopsies without crush artifacts. The freezing time of TBCB was empirically selected from 3 to 7 s in the previous studies. However, no consensus has yet been reached regarding the optimal freezing time used in TBCB.

OBJECTIVES

The primary endpoint was biopsy size in different freezing times. The secondary endpoints included sample histological quality, diagnostic confidence, and complications in different freezing times.

METHODS

Patients who were suspected of DPLD requiring histopathological examination for further evaluation were enrolled in this study. Distinct biopsies were obtained by using different freezing times increased from 3 to 6 s sequentially. Samples were reviewed by 2 external expert pathologists.

RESULTS

A total of 33 patients were enrolled, and 143 transbronchial cryobiopsies were taken in this trial. An average of 4.33 samples were taken from each patient. The mean biopsy size of different freezing times from 3 to 6 s was 9.10 ± 4.37, 13.23 ± 5.83, 16.26 ± 5.67, and 18.83 ± 7.50 mm2, respectively. A strong correlation between freezing time and biopsy size was observed (r = 0.99, p < 0.01). Statistically significant difference of biopsy size was detected in the freezing time of 3 s versus 4 s (p < 0.01) and 4 s versus 5 s (p = 0.02), but not in the freezing time of 5 s versus 6 s (p = 0.10). Overall bleeding in different freezing times from 3 to 6 s was 53.33%, 67.50%, 89.47%, and 77.14%, respectively. A significantly higher overall bleeding was observed when the freezing time exceeded 4 s (RR = 1.67, p < 0.01). Pneumothorax occurred in 4 cases (12.12%). One lethal case (3.03%) was noted 25 days after TBCB. Lung parenchyma was preserved well in all cryobiopsy samples. Thirty-one (93.94%) patients' histopathological findings were identified as sufficient to establish a CRP diagnosis. There was no statistical difference in diagnostic confidence between different freezing times.

CONCLUSION

A longer freezing time was associated with a larger size of the biopsy sample but a higher risk of bleeding. The optimal transbronchial cryobiopsy freezing time is 3-4 s, which is easily achievable and provides an adequate biopsy size whilst creating a safety threshold from complications.

Applied pressure of cooling gas: a neglected determinant for size of specimens in transbronchial cryobiopsy

Background

Transbronchial cryobiopsy (TBCB) is an option to surgical biopsy for the diagnosis in interstitial lung diseases. Several impact factors have received wide attention, including the freezing time, cryoprobe size, and contact pressure. However, the effect of the applied gas pressure on the specimen size has not been well elucidated. The purpose of this study is to investigate the effect of the applied gas pressure on the TBCB specimen size.

Methods

Cryoprobes with a diameter of 1.9 mm were used to perform TBCB on 4 beagle canines under general anesthesia. TBCB was performed with a total of 16 time-pressure combinations that were randomly combined with 4 freezing times (3, 4, 5, and 6 s) and 4 gas pressures (40, 50, 55, and 60 bar). For each combination, 8 biopsies were performed. The size and quality of specimens, as well as complications, were evaluated.

Results

A total of 128 TBCB specimens were obtained. With the same freezing time, the specimen sizes obtained by different applied gas pressures were significantly different (P<0.05) and positively correlated with the gas pressures (r: 0.797–0.867). With the same gas pressure, the size of the TBCB specimens was positively correlated with the freezing time (r: 0.503–0.752). In the 40-bar group, no tissues were obtained when the freezing times were 3–5 s. In the 50-bar and 55-bar groups, qualified specimens were obtained when the freezing times were 5 and 6 s. In the 60-bar group, qualified specimens were obtained when the freezing times were 3–6 s.

Conclusions

The TBCB specimen size was positively correlated with the applied gas pressure. The applied gas pressure contributed to the sample size and quality. To obtain qualified specimens with a 1.9-mm cryoprobe during TBCB, the lowest limit of the normal working gas pressure range should be increased to greater than 50 bar.

Transbronchial Cryobiopsy in Interstitial Lung Diseases: State-of-the-Art Review for the Interventional Pulmonologist

Interstitial lung diseases are a heterogenous group of disorders that are often difficult to diagnose precisely. Clinical, laboratory, radiographic, and histologic information may be needed to arrive at the correct diagnosis. The multidisciplinary discussion has been proven to be useful in this patient group. Transbronchial cryobiopsy has become a popular method for obtaining tissue samples. Over the course of the last decade, there has been a significant amount of research assessing the feasibility, safety, and diagnostic endpoints of transbronchial cryobiopsy in patients with interstitial lung disease. Data continues to mount to support its use, which has been reflected in guidelines and expert panel reports. Patient selection, procedural performance, and appropriate specimen handling are critical factors for success. A coordinated approach by pulmonologists with expertise in interstitial lung diseases, interventional pulmonologists, and thoracic pathologists is essential. In this evidence-based narrative review, we address transbronchial cryobiopsies from these three distinct perspectives. In addition, the current literature was used to address nine common procedural questions.

Feasibility and utility of transbronchial cryobiopsy in precision medicine for lung cancer: Prospective single-arm study

Cryoprobe is a novel transbronchial biopsy (TBB) tool that yields larger tissue samples than forceps. Pathological diagnosis and biomarker analysis, such as genetic alterations and programmed death‐ligand 1 (PD‐L1) expression, are paramount for precision medicine against lung cancer. We evaluated the safety and usefulness of cryoprobe TBB for lung cancer diagnosis and biomarker analysis. In this single‐center, prospective single‐arm study, patients suspected of having or diagnosed with primary lung cancer underwent cryoprobe TBB using flexible bronchoscopy after conventional forceps TBB from the same lesion. Cryoprobe TBB was performed in 121 patients. The incidence rate of severe bleeding and serious adverse events (4% [90% confidence interval: 2%‐9%]) was significantly lower than the expected rate (20% with 30% threshold, P < 0.01). Combining both central and peripheral lesions, the diagnostic yield rate of cryoprobe samples was 76% and that of forceps samples was 84%. Compared with forceps TBB samples, cryoprobe TBB samples were larger (cryoprobe 15 mm² vs forceps 2 mm²) and resulted in a larger proportion of definite histomorphological diagnosis (cryoprobe 86% vs forceps 74%, P < 0.01), larger amounts of DNA extracted from samples (median: cryoprobe, 1.60 µg vs forceps, 0.58 µg, P = 0.02) and RNA (median: cryoprobe, 0.62 µg vs forceps, 0.17 µg, P < 0.01) extracted from samples, and tended to yield greater rates of PD‐L1 expression >1% (51% vs 42%). In conclusion, cryoprobe is a safe and useful tool for obtaining lung cancer tissue samples of adequate size and quality, which allow morphological diagnosis and biomarker analysis for precision medicine against lung cancer.

Evaluation of Efficacy of a New Cryoprobe for Transbronchial Cryobiopsy: A Randomized, Controlled in vivo Animal Study

BACKGROUND

Forceps biopsy (FB) is still the most popular procedure for the bronchoscopic sampling of lung tissue. However, it has limitations like inadequate sample size and crush artifacts. Cryobiopsy (CB) has been introduced to obtain bronchoscopic biopsies with improved diagnostic yield compared to FB. Limitations of CB are the need to retract the cryoprobe en bloc with bronchoscope because samples are larger than the working channel and the variations of the freezing power of the reusable CB (rCB). Therefore, 3 new disposable cryoprobes (dCB) have been developed with different outer diameters: 1.1 mm (CB11-S) that can be retracted through the working channel of the bronchoscope, 1.7 mm (CB17) and 2.4 mm (CB24n), respectively.

OBJECTIVES

The aim was to evaluate the new cryoprobes with regard to feasibility, specimen area, specimen quality and complications.

METHODS

We compared biopsy samples of the new probes with those obtained by FB and by rCB in an in vivo (porcine) model. A flexible bronchoscope was used to perform biopsy at 4 different locations at the upper and lower lobes of the right and left lung, respectively. The biopsies were taken under fluoroscopic control. The biopsy tool and activation times were allocated randomly. Altogether 204 biopsy procedures were performed.

RESULTS

The sample quality of the dCB was superior to that of FB (all p < 0.05) and not significantly different to the rCB sample quality. Mean specimen sample area of all CB was significantly larger compared to FB (p < 0.05). The sample area of the small cryoprobe (CB11-S) was significantly smaller compared to the other CB probes (p < 0.05). No severe bleedings occurred. Pneumothoraces were detected in 3 of the 7 pigs.

CONCLUSION

We conclude that CB with the new single-use instruments are feasible and represent a viable option to improve the diagnostic accuracy of histopathological evaluation compared to FB.

Transbronchial Lung Cryobiopsy in Idiopathic Pulmonary Fibrosis: A State of the Art Review

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease associated with significant morbidity and mortality. The diagnosis of IPF involves a combination of clinical history, radiological imaging and examination of histopathological samples in appropriate cases. Historically, transbronchial biopsy (TBB) has been used to obtain histological samples; however this lacks diagnostic accuracy. At present, surgical lung biopsy (SLB) is the gold standard technique for obtaining specimen samples; however this carries a significant mortality risk. Transbronchial lung cryobiopsy (TBLC) is a new technique that has been pioneered in the management of lung malignancy and offers a potential alternative to SLB. The technique employs a freezing probe, which is used to obtain lung tissue samples that are larger and better quality than traditional TBB samples. This affords TBLC an estimated diagnostic yield of 80% in interstitial lung disease. However, with limited evidence directly comparing TBLC to SLB, the diagnostic accuracy of the procedure has been uncertain. Common complications of TBLC include pneumothorax and bleeding. Mortality in TBLC is low compared with SLB, with exacerbation of IPF frequently reported as the cause. TBLC represents an exciting potential option in the diagnostic pathway in IPF; however its true value has yet to be determined.

[Transbronchial cryobiopsy in diffuse interstitial lung diseases]

INTRODUCTION

In the diagnostic approach to interstitial lung disease (ILD), the use of transbronchial cryobiopsy (TBC) may offer an alternative to surgical lung biopsy (SLB). We report the diagnostic effectiveness and the safety of TBC in ILD based on the preliminary experience in two French university centers.

METHODS

Twenty four patients underwent TBC for the diagnosis of ILD in the operating room between 2014 and 2017. All the histological diagnoses obtained were then reviewed and validated during multidisciplinary discussions (MDD).

RESULTS

Patients had an average of 3 TBC.TBC samples were analyzable in 22/24 (91.7%) patients. In these, samples allowed a histological diagnosis to be made in 14/22 (63.6%) patients and a diagnosis with certainty in 13/22 (59%) after MDD. The overall diagnostic yield from TBC was 13/24 (54.2%). Nine (37.5%) patients had a pneumothorax. Five (20.8%) patients had a bleeding. There were no deaths. Taking into account a possible initial learning curve and considering only the 15 patients who had their TBC after 2015, we note that a diagnosis could be made after MDD for 12 of them, that is, 80%.

CONCLUSION

A prospective randomized study is needed to evaluate the technique in France in order to specify its diagnostic performance and its safety profile in comparison to SLB.

Bronchoscopic lung cryobiopsy: An Indian association for bronchology position statement

BACKGROUND

Bronchoscopic lung cryobiopsy (BLC) is a novel technique for obtaining lung tissue for the diagnosis of diffuse parenchymal lung diseases. The procedure is performed using several different variations of technique, resulting in an inconsistent diagnostic yield and a variable risk of complications. There is an unmet need for standardization of the technical aspects of BLC.

METHODOLOGY

This is a position statement framed by a group comprising experts from the fields of pulmonary medicine, thoracic surgery, pathology, and radiology under the aegis of the Indian Association for Bronchology. Sixteen questions on various technical aspects of BLC were framed. A literature search was conducted using PubMed and EMBASE databases. The expert group discussed the available evidence relevant to each question through e-mail and a face-to-face meeting, and arrived at a consensus.

RESULTS

The experts agreed that patients should be carefully selected for BLC after weighing the risks and benefits of the procedure. Where appropriate, consideration should be given to perform alternate procedures such as conventional transbronchial biopsy or subject the patient directly to a surgical lung biopsy. The procedure is best performed after placement of an artificial airway under sedation/general anesthesia. Fluoroscopic guidance and occlusion balloon should be utilized for positioning the cryoprobe to reduce the risk of pneumothorax and bleeding, respectively. At least four tissue specimens (with at least two of adequate size, i.e., ≥5 mm) should be obtained during the procedure from different lobes or different segments of a lobe. The histopathological findings of BLC should be interpreted by an experienced pulmonary pathologist. The final diagnosis should be made after a multidisciplinary discussion. Finally, there is a need for structured training for performing BLC.

CONCLUSION

This position statement is an attempt to provide practical recommendations for the performance of BLC in DPLDs.

Cryobiopsy in the Upper Urinary Tract: Preclinical Evaluation of a Novel Device

OBJECTIVE

To develop a novel device for cryobiopsy of the upper urinary tract (UUT) and to evaluate its feasibility in a standardized preclinical setting.

MATERIALS AND METHODS

Flexible cryoprobes (diameter 0.9 mm; cooling agent CO2) were developed and used to extract biopsies in porcine UUTs. Cryosamples obtained by ureterorenoscopy were systematically compared with biopsy specimens obtained with standard of care devices in terms of physical characteristics (deflection angle and irrigation flow rates) and histologic criteria (assessability).

RESULTS

Irrigation flow rates were significantly higher with introduced BIGopsy (2.8 ± 0.1) compared with standard forceps (0.94 ± 0.06; P < .001) and cryoprobe (1.1 ± 0.1; P < .001). Angular deflection was significantly reduced by the inserted cryoprobe (130.7° ± 1.2° vs 166.9° ± 1.1° [BIGopsy] or 161.4° ± 1.9° [standard forceps]; both P < .001). Significantly larger UUT tissue samples were obtained by the cryoprobe (mean specimen area 7.5 ± 2.5 vs 4.6 ± 2.5 mm² [BIGopsy] or 1.4 ± 1.4 mm² [standard forceps]; both P < .001). No crush artifacts were observed in cryosamples. Superior histologic assessability scores were achieved in samples obtained by the cryoprobe (mean 2.8 ± 0.8) and BIGopsy (2.3 ± 1.9) when compared with standard forceps (0.4 ± 0.9; P < .001).

CONCLUSION

Cryobiopsy in the UUT is feasible and represents a viable new option to improve the diagnostic accuracy of histopathologic evaluation. Larger and more representative tissue samples can be obtained using a cryoprobe and artifacts may be avoided. Further optimization of the probe will reduce possible restrictions of ureterorenoscopy handling when the device is inserted.

Feasibility and Safety of Pleuroscopic Cryobiopsy of the Pleura: A Prospective Study

Background

The aim of this study was thus to evaluate the feasibility and safety of taking biopsy specimens by cryoprobe from the parietal pleura during semirigid pleuroscope.

Methods

In a single-center, observational, prospective study, patients with exudative pleural effusion (EPE) were evaluated with a semirigid pleuroscope between January 2015 and July 2017. Each patient underwent pleural biopsy using flexible forceps and flexible cryoprobe through pleuroscope following diagnostic thoracentesis and closed pleural biopsy (CPB).

Results

A total of 92 patients (median age 64 years) were included in the study, most of whom were men (65.2%). Cytological cell block (CCB) and CPB made definitive diagnoses in 32/92 (34.8%) and 25/92 (27.5%), respectively; flexible forceps biopsy (FFB) and cryoprobe biopsy (CB) established definitive diagnoses in 84/92 (91.3%) and 91/92 (98.9%), respectively. The sample obtained by CB (9.4 ± 4.9 mm) was significantly larger than the other two methods: FFB (4.2 ± 2.3 mm) or CPB (1.9 ± 1.0 mm) (P < 0.0001). The immunohistochemical (IHC) staining was more easily performed with CB (98.9%) compared to either FFB (87.0%) or CPB (13.0%). There were no significant complications or procedure-related deaths.

Conclusions

Based on these results, CB during semirigid pleuroscope has a high diagnostic yield, differentiating EPE of unknown etiology with satisfactory effectiveness and safety.

Malignant central airway obstruction

This review comprehensively describes recent advances in the management of malignant central airway obstruction (CAO). Malignant CAO can be a dramatic and devastating manifestation of primary lung cancer or metastatic disease. A variety of diagnostic modalities are available to provide valuable information to plan a therapeutic intervention. Clinical heterogeneity in the presentation of malignant CAO provides opportunities to adapt and utilize endoscopic technology and tools in many ways. Mechanical debulking, thermal tools, cryotherapy and airway stents are methods and instruments used to rapidly restore airway patency. Delayed bronchoscopic methods, such as photodynamic therapy (PDT) and brachytherapy can also be utilized in specific non-emergent situations to establish airway patency. Although data regarding the success and complications of therapeutic interventions are retrospective and characterized by clinical and outcome measure variability, the symptoms of malignant CAO can often be successfully palliated. Assessment of risks and benefits of interventions in each individual patient during the decision-making process forms the critical foundation of the management of malignant CAO.

Transbronchial cryobiopsy in interstitial lung disease: experience in 106 cases - how to do it

Transbronchial biopsy using forceps (TBB) is the first diagnostic technique performed on patients with interstitial lung disease (ILD). However, the small size of the samples and the presence of artefacts in the tissue obtained make the yield variable. Our objectives were 1) to attempt to reproduce transbronchial cryobiopsy under the same conditions with which we performed conventional TBB, that is, in the bronchoscopy unit without intubating the patient and without fluoroscopy or general anaesthesia; 2) to describe the method used for its execution; and 3) to analyse the diagnostic yield and its complications. We carried out a prospective study that included 106 patients with clinical and radiological features suggestive of ILD who underwent cryo-transbronchial lung biopsy (cryo-TBB) under moderate sedation without endotracheal intubation, general anaesthesia or use of fluoroscopy. We performed the procedure using two flexible bronchoscopes connected to two video processors, which we alternated until obtaining the number of desired samples. A definitive diagnosis was obtained in 91 patients (86%). As for complications, there were five pneumothoraces (4.7%) and in no case was there severe haemorrhage or exacerbation of the underlying interstitial disease. Cryo-TBB following our method is a minimally invasive, rapid, safe and economic technique that can be performed in a bronchoscopy suite under moderate sedation without the need for intubating the patient or using fluoroscopy and without requiring general anaesthesia.

Comparison of Transbronchial and Cryobiopsies in Evaluation of Diffuse Parenchymal Lung Disease

BACKGROUND

Diffuse parenchymal lung diseases (DPLDs) are common. An accurate diagnosis is essential due to differences in etiology, clinicopathologic features, therapeutic options, and prognosis. Transbronchial lung biopsies (TBLBs) are often limited by small specimen size, crush artifact, and other factors. Transbronchial lung cryobiopsies (TBLCs) are under investigation to overcome these limitations.

METHODS

We conducted a retrospective study of 56 patients in a single, tertiary-care academic center to compare the yield of both techniques when performed in the same patient. Patients underwent flexible bronchoscopy using moderate sedation with TBLB followed by TBLC in the most radiographically abnormal areas. Clinical data and postprocedural outcomes were reviewed, with a final diagnosis made utilizing a multidisciplinary approach.

RESULTS

The mean age of patients was 60 years and 54% were male. Comorbidities included COPD (14%) and prior malignancy (48%). The number of TBLB specimens ranged from 1 to 10 per patient (mean 4) and size varied from 0.1 to 0.8 cm. The number of TBLC specimens ranged from 1 to 4 per patient (mean 2) and size ranged from 0.4 to 2.6 cm. Both techniques provided the same diagnosis in 26 patients (46%). An additional 11 (20%) patients had a diagnosis established by adding TBLC to TBLB. Compared with TBLB, TBLC had a higher diagnostic yield in patients with hypersensitivity pneumonitis and interstitial lung disease. Only 2 patients required video-assisted thoracoscopic surgery to establish a diagnosis. Complications included pneumothorax (20%) and massive hemoptysis (2%).

CONCLUSION

TBLC used with TBLB can improve the diagnostic yield of flexible bronchoscopy in patients with DPLD.

Intra-patient comparison of parietal pleural biopsies by rigid forceps, flexible forceps and cryoprobe obtained during medical thoracoscopy: a prospective series of 80 cases with pleural effusion

BACKGROUND

There is only few data available on the use of cryotechnique during medical thoracoscopy.

METHODS

Medical thoracoscopy was performed in consecutive patients with pleural effusion. Prospectively, biopsies were taken by rigid forceps, flexible forceps and cryoprobe. Specimen size, depth and diagnostic yield were compared.

RESULTS

80 Patients were included. 408 biopsies were taken (205 rigid biopsies, 104 flexible biopsies, 99 cryobiopsies). Mean surface area of rigid biopsies was 22.6 ± 20.4 mm(2) (flexible biopsies: 7.1 ± 9.3 mm(2), cryobiopsies: 14.4 ± 12.8 mm(2)). Rigid biopsies were significantly larger than cryobiopsies (p < 0.001) and flexible biopsies (p < 0.001), crybiopsies were significantly larger than flexible biopsies (p < 0.01). A deep biopsy containing fatty tissue was harvested in 63 % of rigid biopsies (cryobiopsy: 49.5 % flexible biopsy: 39.5 %). In 79/80 cases (98.7 % 95 % CI cannot be calculated) a diagnosis was obtained by rigid biopsy (cryobiopsy: 73/80 cases (91.3 % 95 % CI 86.0 - 96.5 %), flexible biopsy: 74/80 cases (92.5 % 95 % CI 88.6 - 97.4 %)). Diagnostic yield achieved with cryobiopsies was inferior to the yield of rigid biopsies (Difference: 12.7 %), but non-inferior to flexible biopsies (Difference: 6.5 %).

CONCLUSION

Cryobiopsies in medical thoracoscopy are safe with high diagnostic yield, non-inferior to flexible biopsies with increased tissue quantity and quality. Cryotechnique can develop an important role in medical thoracoscopy in the near future when rigid thoracoscopy is not available.

Evaluation of Transbronchial Lung Cryobiopsy Size and Freezing Time: A Prognostic Animal Study

BACKGROUND

Transbronchial lung biopsy using a cryoprobe is a novel way of sampling lung parenchyma. Correlation of freezing time with biopsy size and complications has not been evaluated in vivo.

OBJECTIVES

The primary aim of the study is to evaluate the correlation between transbronchial cryobiopsy freezing time and size. The secondary aims are to evaluate histological quality of the biopsy and evaluate procedure-associated complications.

METHODS

Transbronchial lung cryobiopsies were obtained from two anaesthetised sheep using a 1.9-mm cryoprobe inserted into a flexible bronchoscope under fluoroscopic guidance. Freezing times ranged from 1 to 6 s (n = 49). The cryobiopsies were evaluated histologically with respect to their size and quality. Complications of bleeding and pneumothorax were recorded.

RESULTS

The mean cross-sectional area of the cryobiopsy ranged from 4.7 ± 2.1 to 15.7 ± 15.3 mm2. There was a significant positive correlation between increasing freezing time and cryobiopsy cross-sectional area (p = 0.028). All biopsies contained lung tissue with preserved parenchyma. Crush and freeze artefacts were not observed and tissue architecture was intact in all specimens. Small blood vessels and terminal bronchioles were observed in 88% of specimens. All cryobiopsies caused nil or mild haemorrhage with the exception of only 1 episode of severe haemorrhage at 6 s freezing time. Pneumothoraces occurred at 2, 5 and 6 s freezing time and required chest tube insertion. The most significant haemorrhage and pneumothoraces occurred at 5 and 6 s. Our results suggest an initial freezing time of 3 s can provide the maximal biopsy size while minimising major complications.

CONCLUSION

The optimal transbronchial cryobiopsy freezing time is initially 3 s. This time is associated with minimal complications and large artefact-free biopsies.

A New Tool for Transbronchial Cryobiopsies in the Lung: An Experimental Feasibility ex vivo Study

BACKGROUND

Transbronchial cryobiopsy (TBCB) is a minimally invasive procedure to establish a diagnosis of interstitial lung disease though with the disadvantage that samples have to be extracted together with the bronchoscope.

OBJECTIVES

The aim of the present study was to evaluate the feasibility of a new cryoprobe with which biopsy samples can be obtained through the working channel of the flexible bronchoscope.

METHODS

The feasibility of obtaining transbronchial specimens with TBCB was tested and the technique was compared to transbronchial forceps biopsy (TBFB) in a prospectively randomized ex vivo animal study using a standard flexible bronchoscopy technique. The rate of successful biopsies and the duration of the sampling procedure were recorded for both methods. Size and quality of the biopsies were histologically evaluated and measured.

RESULTS

Biopsy samples could be obtained in 93.3% of TBCB and in 79.0% of TBFB procedures (p = 0.182). Sampling procedure time did not differ in any clinically relevant manner between the two methods. The mean specimen area of TBCB samples was significantly higher compared to that of TBFB samples (8.08 ± 5.80 vs. 2.61 ± 2.14 mm2; p < 0.0001). TBCB specimens showed less artifacts and a significantly higher percentage of alveolar tissue (53.57 vs. 25.42%; p = 0.0285) than TBFB specimens.

CONCLUSIONS

It is feasible to retrieve TBCB samples of good quality and size with the new mini cryoprobe through the working channel of the bronchoscope, while the bronchoscope remains within the central airways throughout the whole procedure. Further studies are necessary to evaluate the safety and efficacy in an in vivo setting.

Cryobiopsy in the diagnosis of diffuse interstitial lung disease: yield and cost-effectiveness analysis

BACKGROUND

Assessment of patients with suspected interstitial lung disease (ILD) includes surgical lung biopsy (SLB) when clinical and radiological data are inconclusive. However, cryobiopsy is acquiring an important role in the ILD diagnostic process. The objective of this study was to evaluate the diagnostic yield, safety and economic costs of the systematic use of cryobiopsy in the assessment of patients with suspected ILD.

METHODS

This was a retrospective observational study of patients who had undergone transbronchial cryobiopsy for evaluation of ILD from January 2011 to January 2014. The procedures were performed with a video bronchoscope using a cryoprobe for the collection of lung parenchyma specimens, which were analyzed by pathologists. Diagnostic yield, complications and economic costs of this technique were analyzed.

RESULTS

Criobiopsy specimens from a total of 33 patients were included. A specific diagnosis was obtained in 26, producing a diagnostic yield of 79%. In 5 patients, SLB was required for a histopathological confirmation of disease, but the procedure could not be performed in 4, due to severe comorbidities. The most frequent complications were pneumothorax (12%) and gradei (9%) or gradeii (21%) bleeding. There were no life-threatening complications. The systematic use of cryobiopsy saved up to €59,846.

CONCLUSION

Cryobiopsy is a safe and potentially useful technique in the diagnostic assessment of patients with ILD. Furthermore, the systematic use of cryobiopsy has an important economic impact.

Transbronchial cryobiopsy in immunocompromised patients with pulmonary infiltrates: a pilot study

BACKGROUND

In immunocompromised patients with pulmonary infiltrates, transbronchial lung biopsies (TBB) obtained by forceps has been shown to increase the diagnostic yield over simple bronchoalveolar lavage. Cryo-TBB is a novel modality for obtaining lung biopsies. We aimed to evaluate for the first time the efficacy and safety of cryo-TBB in immunocompromised patients.

METHODS

Fifteen immunocompromised patients with pulmonary infiltrates underwent cryo-TBB. During the procedure two to three biopsy samples were taken. Procedure characteristics, complications, and the diagnostic yield were retrospectively evaluated.

RESULTS

Most patients (n = 11) were immunocompromised due to hematological malignancies. The remaining four patients were receiving chronic immunosuppressive treatment due to previous solid-organ transplantation (n = 2) or collagen-vascular disease (n = 2). No major complications occurred in the cryo-TBB group. The mean surface area of the specimen taken by cryo-TBB was 9 mm(2). The increase in surface area and quality of biopsy samples translated to a high percentage of alveolated tissue (70 %) that enabled a clear histological detection of the following diagnoses: noncaseating granulomatous inflammation (n = 2), acute interstitial pneumonitis consistent with drug reaction (n = 5), nonspecific interstitial pneumonia fibrotic variant (n = 1), diffuse alveolar damage (n = 3), organizing pneumonia (n = 3), and pulmonary cryptococcal pneumonia (n = 1). Diagnostic information obtained by cryo-TBB led to change in the management of 12 patients (80 %).

CONCLUSION

Cryo-TBB in immunocompromised patients with pulmonary infiltrates provides clinically important diagnostic data with a low complication rate. These advantages should be further compared with traditional forceps TBB in a prospective randomized trial.

The cryo-needle: a new tool for histological biopsies. A feasibility study

PURPOSE

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure for intrathoracic lymph node biopsies. The newly developed cryo-needle operates in a similar way to the EBUS-TBNA but is able to obtain specimens for histological evaluation. The purpose of this animal study was to evaluate the feasibility, effect, and safety of the cryo-needle biopsies.

METHODS

Four EBUS-guided cryo-needle biopsies were obtained from a mediastinal lymph node of a healthy pig. In an open surgery approach, cryo-needle biopsies using activation times of 1, 2, and 3 s (A1/A2/A3) and needle biopsies using a 21-gauge EBUS-TBNA needle were obtained from mesenteric lymph nodes. Cryo-needle biopsies A2 were performed with (A2+) and without (A2-) an oversheath. The size, weight, percentage of lymphatic tissue and artefact-free area of each cryobiopsy were evaluated. Smears were made with the TBNA-needle aspirates to determine the number of lymphocytes per high-power field (HPF). The bleeding duration was measured.

RESULTS

We successfully obtained EBUS-guided cryo-needle biopsies. The area and weight of the biopsies A3 and A2+ were significantly larger compared with A1 (1.7 ± 0.8 and 1.4 ± 0.3 vs. 0.9 ± 0.4 mm(2); 5.2 ± 2.4 and 3.4 ± 1.8 vs. 1.5 ± 0.7 mg). The percentage of lymphatic tissue of the cryobiopsies was 90 ± 25 and 98 % of samples were artefact-free. The number of lymphocytes/HPF of TBNA-needle smears was 128 ± 54.3. There was no difference in bleeding duration between the techniques.

CONCLUSIONS

The cryo-needle yields large histological specimens of high quality.

Assessment on the potential role of applying cryoprobe for tissue ablation

Background/Aims

Cryotherapy is the therapeutic application for tissue ablation. Clinical applications of cryotherpy such as in pulmonology have increased. Until now, its development in gastroenterology has been insignificant. But, as clinical application such as mucosal ablation on Barrett's esophagus became possible, various applications have been developed. Therefore, it is important to make standards of tissue injury's extent in cryotherapy prior to clinical trial. We evaluated the tissue injury according to the application of cryoprobe with a pig model.

Methods

Cryoprobe was applied to several different segments of the esophagus and stomach for various lengths of time using various number of probe's contact in a pig model. After 48 hours, esophagus and stomach were harvested and histological tissue injury was assessed. The extent of tissue injury was decided by the injury of the deepest layer.

Results

Endoscopic application of cryoprobe on esophagus and stomach resulted in a dose-dependent injury: esophageal necrosis was limited to the submucosa after 10 seconds of cryotherapy, and extended to involve the transmural necrosis after over 15 seconds. Necrosis on stomach was extended to involve the transmural necrosis after over 20 seconds.

Conclusions

Positive relationship was seen between the duration and frequency of cryoprobe application and the extent of tissue injury.